1. Field of the Invention
The present invention relates to a variable-viscosity, insecticidal delivery formulation composed of a liquid carrier, e.g., water or oil, and one or more solid superabsorbent polymers with one or more liquid or solid insecticidal or noninsecticidal film-forming or surface-active agents, ovicides, larvicides, pupicides, insecticides, biological control agents, pathogens, parasites, microbial control agents, insect growth regulators, conventional toxicants, pesticides, or chemosterilants, with or without herbicides or attractants, repellents, pheromones, alcohols, diluents, or other additives. The present invention also relates to a method of applying the insecticidal delivery composition with one or more active insecticidal ingredients, with or without one or more herbicides or other additives, as variable-viscosity sprays or sols to an aquatic environment having a natural population of aquatic environment insects, for the purpose of controlling that population of insects. The present invention also relates to the use of the insecticidal delivery composition for a pretreatment application to an aquatic insect dry habitat in order to control that population of aquatic insects that will breed when the insect habitat becomes flooded by rain or tides. This invention further relates to a facile method of combining two or more active insecticidal ingredients in a liquid carrier, e.g., water or oil, with one or more film-forming agents, and one or more superabsorbent polymers, with or without one or more herbicides or other additives, to formulate variable-viscosity insecticidal delivery compositions that are flowable (i.e., sprayable, pumpable, or injectable) for ground or aerial application. The application of superabsorbent polymers makes possible the mixing of active insecticidal and herbicidal ingredients that would otherwise be difficult or substantially impossible to mix homogeneously in a liquid carrier, e.g., water or oil, as joint- or multiple-action formulations for spray application. Furthermore, this invention relates to the use of one or more superabsorbent polymers in the formulation of a variety of sprayable/flowable insecticide compositions to synergize, enhance, activate, carry, disperse, release, stabilize, bind, couple, encapsulate, agglomerate, regulate, thicken, suspend, preserve, protect, etc., one or more of the active and/or inactive formulation components in the flowable formulation and/or in the target aquatic, semi-aquatic, or pretreatment environment(s) in which the formulation is applied, in a manner that will provide improved flowable formulations, more efficient formulating (mixing) procedures, more efficient application, and/or generally improve the insecticidal efficacy (performance) of the resultant formulation against the target organism(s).
2. General Background
In particular, the present invention is directed against mosquitoes that breed in permanent or semipermanent, natural or artificial, aquatic habitats. Mosquitoes of major importance to be controlled by the present invention are species of the genera of Aedes, Anopheles, Culex, Culiseta, Coquillettidia, Deinocerites, Mansonia, Orthopodomyia, Psorophora, Uranotaenia and Wyeomyia. It is the main objective of this invention to direct the use of the flowable insecticidal delivery compositions(s) for the control of the immature aquatic states of various species of mosquitoes before they become biting adults capable of being a nuisance and/or transmitting a disease. This technique is cost-effective and reduces the environmental and health hazards that can result when insecticides are extensively broadcast over large areas for the control of the adult stages.
In addition to mosquitoes, other species of aquatic environment insects such as biting and nonbiting midges, black flies, moth flies, crane flies, horse flies, deer flies, hover or flower flies can constitute a nuisance and often a health threat to humans and livestock. Thus, their growth as a population, if unchecked, can be detrimental. The medical and veterinary importance of various species of mosquitoes and other important aquatic environment insects are discussed in detail by Robert F. Harwood and Maurice T. James in, Entomology In Human and Animal Health, Seventh Edition, 1979, MacMillan Publishing Co., Inc., New York, N.Y., which is incorporated herein by reference. Therefore, the scope of the present invention also relates to the use of the flowable insecticidal delivery composition with one or more active insecticidal ingredients, with or without one or more herbicides or other additives, for controlling various species of aquatic environment insects other than mosquitoes.
Various compositions and methods for controlling and killing insects are well known. A number of patents discuss the use of pesticides or insecticides. U.S. Pat. No. 3,535,423 discloses a wettable powder pesticide concentrate that may be dispersed in water. This is described as allowing the otherwise insoluble pesticide to become soluble in water. U.S. Pat. No. 4,267,280 discloses controlled release pesticides and their preparation. These pesticides are described as polymers with a macro-molecular backbone and pendant groups having pesticidal groups chemically linked thereto and prepared by reacting a pesticide having a replaceable hydrogen with a multifunctional isocyanate to form an adduct which is then reacted with a polyol polymer substrate. U.S. Pat. Nos. 4,400,391 and 4,401,456 disclose the use of alginate gel beads to encapsulate bioactive materials to provide for their controlled release. The patents describe beads being made to either float or sink and they may contain insecticides. These beads are also described as acting as carriers to place the bioactive material near the target species, for example, a floating bead containing a herbicide releasing the herbicide in close proximity to floating aquatic weeds or the beads falling through foliage to release a herbicide into the soil. U.S. Pat. No. 4,344,857 contains a disclosure that is similar to those immediately above; however, it involves encapsulation by xanthate derivatives and does not disclose the ability to be used in conjunction with an aqueous environment.
A number of patents describe the use of substances other than pesticides to control the growth of insects. U.S. Pat. No. 4,053,627 discloses a controlled release system for juvenile hormones in aqueous environments. This is described as being accomplished with alginate gel discs comprising alginate, a solubilizing agent, and a salt which yields cations, and containing the juvenile hormone. U.S. Pat. No. 4,160,033 discloses a method for the control of mosquitoes by the use of film-forming materials. The method is disclosed as involving the use of a film of organic material which reduces the surface tension of the body of water, and subsequently causes the mosquito larvae and pupae to drown.
At the present time, ground and aerial application of non-petroleum film-forming agents such as Arosurf.RTM. MSF for mosquito control is performed mainly by spraying the technical liquid or vigorously agitated suspensions of the film-forming agent and water. However, technical film-forming agent(s) such as Arosurf.RTM. MSF applied as conventional liquid sprays are usually adversely effected by wind drift and cannot penetrate dense vegetation at the low recommended application rates. Therefore, most of the costly insecticidal film-forming agent impinges on the vegetation and does not reach the water where the mosquitoes are breeding and/or is translocated by the wind to areas not intended for application. In addition, the use of water as a diluent for application of large volumes for easier vegetative penetration without overdosing requires frequent high-speed/high-shear agitation or the use of high-pressure/high-shear, water-injection systems to adequately suspend the film-forming agent in the water for accurate application rates. Mosquitocidal film-forming agents such as Arosurf.RTM. MSF are virtually insoluble in water, and therefore require continuous or frequently repeated high-shear agitation to effectively suspend or resuspend the Arosurf.RTM. MSF in the water carrier.
The aqueous absorbency mechanism of acrylic-based superabsorbent polymers has been described by the Chemdal Corporation (Arlington Heights, Ill. 60004) in their Technical Data Sheets on Aridall.RTM. Superabsorbent Polymers. The absorbency of acrylic-based superabsorbent polymers is due to carboxylic groups located on the backbone of the superabsorbent polymer. When water contacts the superabsorbent polymer, these groups solvate rapidly and develop mutually repulsive negative charges. This causes the superabsorbent polymer to uncoil and absorb many times its weight in water. Crosslinking prevents solution of the superabsorbent polymer. The aqueous medium rapidly becomes oriented on the surface of the superabsorbent polymer by virtue of hydrogen bonding. The resulting gel has remarkable ability to hold the aqueous medium even under pressure. Superabsorbent polymers hold fluids by a physiochemical mechanism.
None of the prior art methods or compositions for controlling insect populations are without disadvantages. One major problem associated with many of the aforementioned compositions and methods of the prior art is their inability to simultaneously apply immiscible, or otherwise incompatible substances to the area to be treated. It has been found that while film-forming materials, when combined with water and ovicides, larvicides, pupicides, insecticides, pesticides, conventional toxicants, biological control agents, microbial control agents, pathogens, parasites, chemosterilants, or insect growth regulators, with or without herbicides or diluents such as attractants, repellents, pheromones, alcohols, etc., may produce improved insect controlling efficacy over single active component formulations, problems with mixing the ingredients homogeneously often result. For example, blends of Arosurf.RTM. MSF (a film-forming agent) and water or technical and/or water-base blends or Arosurf.RTM. MSF and various formulations of Bacillus thuringiensis var. israelensis (B.t.i.), or Bacillus sphaericus or Abate.RTM. 4-E do not form homogeneous and stable suspensions when casually mixed, and therefore require frequent and vigorous agitation. When allowed to stand, the components would separate into distinct layers because of the differences in their respective specific gravities, and/or the presence of incompatible active and/or inert formulation ingredients, and therefore, these joint- or multiple-action formulations would require continuous agitation and/or reagitation to effectively remix the components just prior to their application. (See Levy et al. 1984, Mosquito News 4:537-543; Levy et al. 1986. Journal of the American Mosquito Control Association 2:233-236.) These mixing and remixing requirements make it very difficult to apply these liquid (aqueous) formulations by conventional means.
While it may be possible to incorporate some known insecticidal components, singly, jointly or multiply as aqueous- or oil-base sprays, these formulations cannot regulate (retard) the release rate of active insecticidal components, and lack the ability to control both mosquito larvae and pupae simultaneously while effectively and spontaneously spreading the active ingredients over the target aquatic habitat.
Since other flowable insecticidal compositions do not have rapid self-spreading characteristics, they require even applications to assure that there is effective control of the target aquatic insects that may be widely dispersed in the aquatic habitat. In addition, the other flowable insecticidal components usually affect only one immature developmental stage. However, the use of insecticidal delivery compositions made with one or more superabsorbent polymers of the present invention with, for example, a pupicidal film-forming agent (e.g., Arosurf.RTM. MSF), a larvicidal agent such at B.t.i. or Bacillus sphaericus, and water, have self-spreading potential and can kill mosquito larvae, pupae, or emerging adults rapidly in areas far removed from the initial points of application, significantly better than either of the active formulation components. These formulations can also kill floating eggs and egg rafts of certain species of mosquitoes and also entrap and drown females that oviposit on the surface of the water. Although Arosurf.RTM. MSF can kill mosquito larvae and pupae, its impact on larval populations is usually very slow and requires higher application rates than for pupal control.
No single-, joint-, or multiple-action flowable, water-compatible formulations are available that claim rapid larvicidal and pupicidal action with some degree of ovicidal and adulticidal action, self-spreading characteristics, and field persistence. For example, commercial mosquitocidal preparations of Bacillus thuringiensis var. israelensis formulated for water-base spray applications (e.g., Vectobac.RTM. -AS, Vectobac.RTM. -12AS; Teknar.RTM., Teknar.RTM. HP-D, Teknar.RTM. WDC; Bactimos.RTM. Wettable Powder; Skeetal.RTM.F), Bacillus sphaericus (BSP-1), Abate.RTM. 4-E, Dursban.RTM., Baytex.RTM. 4 and Baytex.RTM. LC, Furadan.RTM., Baygon.RTM. 70% wettable powder, Dimilin.RTM. wettable powder, Altosid.RTM. Liquid Larvicide are available that have slow or quick immature stage kill potential; however, these do not have rapid multi-developmental stage control potential, do not have self-spreading characteristics, are typically composed of only one active insecticidal ingredient that cannot be simply and rapidly detected or monitored under field conditions by insecticide applicators, and are not formulated with superabsorbent polymers.
Attempts have been made to incorporate film-forming agents such as those described in U.S. Pat. No. 4,160,033 with a variety of conventional insecticides in water (See Levy et al. 1984, Mosquito News: 44 pp. 537-543, pp. 592-595; Levy et al. 1986, Journal American Mosquito Control Association 2:233-236). However, these attempts have been unsuccessful because the film-forming agent (i.e., Arosurf.RTM. MSF) would readily separate into layers even after vigorous agitation due to incompatibilities of the film-forming agent with water or other insecticides and/or inert ingredients in the formulation. Therefore, the resultant formulations could not be homogeneously mixed to assure that accurate application rates of the active components would be applied in the field against the target aquatic pest.
Specific Objects
It is therefore an object of the present invention to provide flowable, aqueous- or oil-base superabsorbent polymer compositions and methods for the pretreated dry habitat control and aquatic control of a population of aquatic environment insects, particularly mosquitoes, which overcome the problems and deficiencies of the prior art.
It is also an object of the present invention to provide flowable, aqueous- or oil-base superabsorbent polymer compositions and methods which are easy to prepare (formulate) and use (apply), and which are erodible (biodegradable) and safe to the environment, but which is effective for use in controlling one, but preferably more than one immature stage of a natural population of aquatic environment insects, particularly mosquitoes.
It is further an object of the present invention to provide superabsorbent polymer compositions and methods which can incorporate a wide variety of ingredients into a single flowable, aqueous- or oil-base insecticidal delivery formulation to control a broad spectrum of aquatic environment insect populations, particularly mosquitoes, and to provide for the variable time-release of those ingredients.
These and other objects are accomplished by the compositions and methods of the present invention.
Specific Aspects
In accordance with one aspect of the present invention, there is provided flowable, aqueous- or oil- base insecticidal delivery compositions for controlling a population of aquatic environment insects, the flowable delivery compositions being applied as a pretreatment before the target habitat is flooded or as a direct treatment to the aquatic habitat. The composition includes at least one superabsorbent polymer, and at least one insecticidal agent, alone or in combination with a diluent or surface-active agent, the superabsorbent polymer and insecticidal agent being present in a total amount effective to control the population of aquatic environment insects. The superabsorbent polymer(s) being present at a concentration adapted to allow satisfactory mixing of the formulation components and release modification of the insecticidal agent(s) from the flowable formulation.
In accordance with another aspect of the present invention, there is provided flowable, aqueous- or oil-base insecticidal delivery compositions for controlling a population of aquatic environment insects which includes at least one superabsorbent polymer, and at least one different insecticidal agent which is a film-forming agent, the superabsorbent polymer and agent being present in a total amount effective to control the population of aquatic environment insects, the delivery compositions being applied as a variable-viscosity pretreatment application before the target habitat is flooded or as a direct treatment to the aquatic habitat.
In accordance with yet another aspect of the present invention, there is provided flowable, aqueous- or oil-base insecticidal delivery compositions for controlling a population of aquatic environment insects which includes at least one superabsorbent polymer, at least one different insecticidal agent which is a film-forming agent, and at least one additional compound. The additional compound is selected from larvicides; pupicides; ovicides; insecticides; toxicants; pesticides; biological control agents; microbial control agents; pathogens; parasites; insect growth regulators; chemosterilants; and mixtures thereof, with or without herbicides; attractants; pheromones; repellents; diluents; alcohols; surface-active agents; etc. The superabsorbent polymer, agent and additional compound are present in a total amount effective to control the population of aquatic environment insects, the flowable, variable-viscosity aqueous- or oil-base delivery compositions being applied as a pretreatment before the target habitat is flooded or as a direct treatment to the aquatic habitat.
In accordance with another aspect of the present invention, there is provided a method for controlling a population of aquatic environment insects which includes the steps of:
preparing flowable, variable-viscosity aqueous- or oil-base insecticidal delivery compositions which includes at least one superabsorbent polymer and at least one insecticidal agent which includes a film-forming agent, by a series of variable time/speed blending, and/or salt/electrolyte conditioning treatments;
applying said flowable, aqueous- or oil-base insecticidal delivery compositions in an amount effective to control the population of aquatic environment insects, to an aquatic area needing aquatic insect control treatment, the flowable, aqueous- or oil-base delivery compositions being applied as a pretreatment before the target habitat is flooded or as a direct treatment to the aquatic habitat.
In accordance with still another aspect of the present invention, there is provided a method for controlling a population of aquatic insects. The method includes the steps of:
preparing flowable, variable-viscosity aqueous- or oil-base insecticidal delivery compositions which includes at least one superabsorbent polymer and a least one insecticidal agent which includes a film-forming agent and at least one additional compound. The additional compound is selected from ovicides; larvicides; pupicides; insecticides; conventional toxicants; pesticides; biological control agents; microbial control agents; pathogens; parasites; insect growth regulators; chemosterilants; and mixtures thereof, with or without herbicides; attractants; repellents; pheromones; diluents; alcohols; surface-active agents; etc.; and
applying said flowable, aqueous- or oil-base insecticidal delivery compositions in an amount effective to control the population of aquatic environment insects, to an aquatic environment needing aquatic insect control treatment before the target habitat is flooded or as a direct treatment to the aquatic habitat.
The superabsorbent polymers of the present invention are synthetic organic polymers which are solid and hydrophilic absorbing over 100 times their weight in water. Generally, these superabsorbent polymers are chosen from acrylamide and acrylate polymers, co-polymers and ter-polymers. These polymers can be suitably crosslinked and/or modified. These superabsorbent polymers are typically in a power, flake, or granular form, adapted to optimize the compatibility and/or release rates of insecticidal components in water or oil and, thereby, enhance the activity of flowable insecticidal formulations against the target aquatic insect.
The acrylamide and acrylate superabsorbent polymers may be, for example, acrylamide alkali metal or alkali metal/aluminum acrylate co-polymers; propenenitrile homo-polymers, hydrolyzed, alkali metal or alkali metal/aluminum salts; polymers of propenamide and propenoic acid, alkali metal salts; hydrolyzed acrylonitrile co-polymers, and starch graft co-polymers and ter-polymers thereof. All of these are designed to be hydrophilic, absorbing over 100 times their weight in water.
The present invention has been found to be particularly effective in controlling natural populations of mosquito species such as Aedes taeniorhynchus, Aedes sollicitans, Anopheles atropos, and Culex nigripalpus that can breed in brackish/salt water habitats. The use of the invention to control species of fresh or polluted water mosquitoes such as Aedes aegypti, Aedes albopictus, Aedes triseriatus, Anopheles quadrimaculatus, Anopheles crucians, Culex quinquefasciatus, Psorophora columbiae, Psorophora ciliata, Wyeomyia mitchellii, Wyeomyia vanduzeei, etc., in semipermanent or permanent aquatic environment areas needing mosquito control treatment is also proposed.
Specific Advantages
The present invention provides numerous advantages over prior compositions and methods to control the population of aquatic environment insects such as mosquitoes. For example, the flowable, aqueous- or oil-base superabsorbent polymer formulations of the present invention may be composed of one or more of a wide choice of either nontoxic or toxic biological or microbial control agents, pathogens, parasites, insect growth regulators, monomolecular surface films, larvicides, ovicides, pupicides, insecticides, chemosterilants, pesticides, and/or toxicants, with or without herbicides or attractants, repellents, pheromones, diluents, alcohols, etc., depending on the type or nature of the habitat to be controlled, the environmental impact, and/or the type of aquatic developmental stage or insect species to be controlled. The superabsorbent polymer formulations of the present invention are flowable (i.e., sprayable, pumpable or injectable) and are mainly based on water; however, these formulations can also be based on oil. The flowable, aqueous- or oil-base superabsorbent polymer formulations of the present invention are biodegradable. They are also storage stable, basically as stable as the individual components; however, increased stability may occur from encapsulation of the active components within the aqueous- or oil-base formulation. Aqueous- or oil-base formulations of the present invention can be of varying viscosities which may be required for a particular application. The flowable formulations of the present invention can have some variable time-release, either quick, or gradual, depending on the concentration and types of superabsorbent polymers in the aqueous- or oil-base formulation. The present invention provides a suspending/compatibility agent to assure homogeneous delivery of joint- or multiple-active, aqueous- or oil-base formulations of otherwise incompatible soluble or insoluble liquid or powdered insecticidal and/or non-insecticidal agents without the necessity of continuous or repetitive high-speed/high-shear agitation for effective spray application of the active components. Flowable, variable-viscosity aqueous- or oil-base formulations of the present invention can be used as a pretreatment application to areas that are dry but are known to breed when flooded, thereby assuring that the first broods will be controlled. Also, encapsulation of the active insecticidal agents within the variable-viscosity, flowable superabsorbent polymer formulation can protect the active components from degradation or decomposition from ultra-violet radiation, microbial action, temperature effects, run-off, etc., when the formulation is applied as a pretreatment application. The present invention is also not restricted to applications to any one type of aquatic environment.
Other objects, aspects and advantages of the present invention will be apparent to one of ordinary skill in the art from the following: